Correlation between flood frequency and geomorphologic complexity of rivers network - A case study of Hangzhou China
Correlation between flood frequency and geomorphologic complexity of rivers network - A case study of Hangzhou China
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DOI：
10.1016/j.jhydrol.2015.04.060
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发表时间：
2015-08
影响因子：
6.4
通讯作者：
Shixia Zhang;Yakun Guo;Ziwen Wang
中科院分区：
文献类型：
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作者：
Shixia Zhang;Yakun Guo;Ziwen Wang
城市洪水是气候和流域地貌共同作用的产物。水系是流域地貌的重要组成部分。河流地貌特征对洪水的形成有重要影响。然而，到目前为止，很少有人试图调查洪水频率，洪水的概率，和河流系统的地貌复杂性之间的关系。这种关系是必不可少的，以预测洪水频率的可能响应的大规模变化的复杂性引起的河流周围的城市化加速的河流网络。在这项研究中，我们探讨了河流系统的地貌特征和洪水的概率之间的相关性。以遭受严重洪涝灾害的杭州市为例，研究了排水管网形态变化对局部洪涝灾害的影响。以杭州市8个次级河网为研究对象，采用基于分形几何学的计盒法计算了河网地貌复杂程度的分维值。建立了基于洪水频率与分形维数相关性的模型。以杭州市两个典型区域为例，研究了城市化进程引起的河流地貌变化对局部洪水频率的影响。结果表明，洪水频率/事件随河网分维的减小而增大，表明河网地貌的复杂性对洪水有重要影响。该研究对今后的洪水定量调查具有重要的参考价值，为城市防洪和水系保护提供了新的方法。
Urban flooding is a combined product of the climate and watershed geomorphology. River system is one of the vital components of watershed geomorphology. The geomorphic characteristics of rivers have important effect on the formation of flooding. However, there have been few attempts so far to investigate the relationship between flooding frequency, the probability of flooding, and the geomorphological complexity of river system. Such relationship is essential in order to predict likely responses of flooding frequency to the large-scale changes in the complexity of the rivers network induced by accelerating urbanization around rivers. In this study we investigate the correlation between geomorphological characteristics of river system and the probability of flooding. Hangzhou city in China, which has suffered severe flooding, is chosen as a case study to evaluate this correlation and to investigate the impact of changes of drainage networks morphology on the local flooding. The fractal dimension, which is used to quantitatively assess geomorphological complexity of rivers network, is calculated by using box-counting method based on fractal geometry for eight sub rivers network in Hangzhou. A model based on the correlation of flooding frequency and fractal dimension is established. The model is applied to investigate the effect of the rapid urbanization induced changes of river geomorphology on the local flood frequency in two typical regions in Hangzhou. The results show that the flood frequency/event increases with the decrease of fractal dimension of the rivers network, indicating that the geomorphologic complexity of rivers network has an important effect on flooding. This research has great referential value for future flood quantitative investigations and provides new method for urban flood control and river system protection.